Title of article :
Performance of Low-Dose Chest CT Scan for Initial Triage of COVID-19
Author/Authors :
Bahrami-Motlagh, Hooman Department of Radiology - Loghman Hakim Hospital - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Abbasi, Sahar Department of Radiology - Loghman Hakim Hospital - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Haghighimorad, Maryam Department of Radiology - Loghman Hakim Hospital - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Salevatipour, Babak Department of Radiology - Loghman Hakim Hospital - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Alavi Darazam, Ilad Department of Infectious Diseases and Tropical Medicine - Loghman Hakim Hospital - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Sanei Taheri, Morteza Department of Radiology - Shohada Tajrish Hospital - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Esmaeili Tarki, Farzad Pediatric Gastroenterology - Hepatology and Nutrition Center - Research Institute for Children’s Health - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Naghibi Irvani, Sina Department of Radiology - Loghman Hakim Hospital - Shahid Beheshti University of Medical Sciences, Tehran, Iran
Abstract :
Background: Chest computed tomography (CT) scan is frequently used for diagnosis of coronavirus disease 2019 (COVID-19), especially in regions with limited availability of reverse-transcription polymerase chain reaction test (RT-PCR) test. Low-dose CT of chest
offers acceptable image quality with lower radiation dose, particularly important in younger patients.
Objectives: We have designed the current study to evaluate the diagnostic efficacy of low-dose chest CT versus early RT-PCR results,
for triage of COVID-19 patients.
Patients and Methods: From February 20 to April 15, 2020, 163 patients including 100 males (61.3%) with the median age of 65
years (21 to 97), who underwent both RT-PCR and chest CT were registered in the study. Low-dose chest CT protocol was applied
with parameters modified from the lung cancer screening protocol. The accuracy of low-dose chest CT for COVID-19 diagnosis was
evaluated, considering first RT-PCR results as reference.
Results: Of 163 patients, 89 cases (54.6%) were presented with positive initial RT-PCR result. Lymphocyte percentage and lymphocyte count were significantly lower in the positive RT-PCR group (15% versus 19%, and 0.98 vs. 1.3, respectively); while, erythrocyte
sedimentation rate (ESR) was significantly higher (53 vs. 22). Positive chest CT findings were present in 133/163 cases (81.6%). The
sensitivity, specificity, positive and negative predictive values (PPV and NPV) and accuracy of low-dose chest CT scan were 96.6% (95%
confidence interval [CI], 90% - 99%), 36.5% (95% CI, 26% - 49%), 64.7% (95% CI, 56% - 73%), 90% (95% CI, 72% - 97%) and 69.3% (95% CI, 61%
- 76%), respectively based on positive RT-PCR results.
Conclusion: Low-dose chest CT scan provides both high sensitivity and negative predictive value in diagnosing COVID-19 compared
to initial RT-PCR as the gold standard. It can be used as an alternate to standard-dose CT scan in areas with high prevalence of COVID-
19 disease and limited availability of RT-PCR for early triage.
Keywords :
Novel Coronavirus 2019 , COVID-19 , Chest CT Scan , Low-Dose Protocol
Journal title :
Iranian Journal of Radiology (IJR)
